A two-armed gas collection pipe of this type, also called bifurcated pipe, has been known from DE 198 15 473 A1. Due to the special shape of the inlet pipe connection of this gas collection pipe, the middle areas are subject to substantially higher thermal load than the upper area and the lower area in its outlet cross section formed by the gas ring channel.
The gas ring channel of the gas collection pipe is cooled to the extent that cooling air is led along the gas ring channel on the outside. This cooling air is taken from the compressor of the gas turbine plant. Two ring flanges, which are provided with slots for the passage of the cooling air into the flow channel of the gas turbine, are provided at the edges of the gas ring channel. In a gas collection pipe known from DE 100 32 454 A1, the cross sections of the slots are distributed nonuniformly over the circumference of the ring flange such that a larger amount of cooling air is carried along at the areas of the gas collection pipe that are subject to a higher thermal load than at the areas that are subject to a lower thermal load. As a result, uniform cooling of the gas ring channel of the gas collection pipe is achieved due to the nonuniform amount of cooling air.